The starting point of this thesis is the assertion that the interaction between individuals and public authorities sometimes produces claims which cannot easily be categorized as public or private law claims – “claims in the twilight zone”. The aims of the thesis are to examine to what extent such claims can be determined by a court of law and to establish to which kind of court such a claim is properly to be submitted. Moreover, assuming that there is a division of competence between the general courts and the administrative courts that purport to “cut through” claims in the twilight zone, the thesis examines three specific interests: 1) the interest of effective adjudication of claims in the twilight zone; 2) the interest of upholding the division of competence between the general courts and the administrative courts; and 3) the interest of avoiding parallel decisions on the same subject matter.

There is much to support the conclusion that claims in the twilight zone have hitherto, with a couple of important exceptions, been adjudicated in the general courts. However, certain ambiguities relating to the proper role of the administrative courts make it uncertain whether this can still be said to be the case. It may perhaps be that the Supreme Court and the Supreme Administrative Court have divergent conceptions of the meaning and effect of a decision made by an administrative court. The present uncertainty makes it difficult to establish to which kind of court a claim in the twilight zone is properly to be submitted, and there is a certain risk that such a claim will not be possible to pursue through a judicial process at all. There is also a certain risk that new boundary lines between public law and private law will be created as a result of procedural ambiguities and not as a result of clear standpoints in matters of substantial law. It is suggested that the situation should be remedied by clarifying the proper role of the administrative courts – or by an amalgamation of the general courts and the administrative courts to one single court system.